metaprogramming.hpp

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// Copyright (c) 2019-2024, Lawrence Livermore National Security, LLC and
// other Serac Project Developers. See the top-level LICENSE file for
// details.
//
// SPDX-License-Identifier: (BSD-3-Clause)
 
#pragma once
 
#include <tuple>
#include <utility>
#include <type_traits>
 
#include "serac/infrastructure/accelerator.hpp"
 
template <int I, int... n>
constexpr auto get(std::integer_sequence<int, n...>)
{
  constexpr int values[sizeof...(n)] = {n...};
  return values[I];
}
 
namespace detail {
 
template <typename T>
struct always_false : std::false_type {
};
 
template <int i>
struct integral_constant {
  SERAC_HOST_DEVICE constexpr operator int() { return i; }
};
 
SERAC_SUPPRESS_NVCC_HOSTDEVICE_WARNING
template <typename lambda, int... i>
SERAC_HOST_DEVICE constexpr void for_constexpr(lambda&& f, integral_constant<i>... args)
{
  f(args...);
}
 
SERAC_SUPPRESS_NVCC_HOSTDEVICE_WARNING
template <int... n, typename lambda, typename... arg_types>
SERAC_HOST_DEVICE constexpr void for_constexpr(lambda&& f, std::integer_sequence<int, n...>, arg_types... args)
{
  (detail::for_constexpr(f, args..., integral_constant<n>{}), ...);
}
 
}  // namespace detail
 
template <int... n, typename lambda>
SERAC_HOST_DEVICE constexpr void for_constexpr(lambda&& f)
{
  detail::for_constexpr(f, std::make_integer_sequence<int, n>{}...);
}